Light signal system for railroads



Sept 22, 1931. I J. E. WILLING 1,824,186

LIGHT SIGNAL SYSTEM FOR RAILROADS Filed Aug. 20, 1930 Patented Sept. 22, 1931 UNITED STATES PATENT OFFICE JOSEPH E. WILLING, OF BOCIIESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK LIGHT SIGNAL SYSTEM FOR RAILR-OADS Application filed August 20, 1930. Serial No. 476,709.

This invention relates in general ;to light signal systems for railways, and hasmore particular reference to animproved circuit for approach lighting signals. (3 It is desirable, in many cases, in railway operation, to indicate the approach of a train to a signal block, by energizing an approach signal at the entrance to the block immediately preceding it.

In the case of a block where the track battery can be placed at one end of the block and the track relay at the other end, it is usual to employ a relay connected in series with the track battery. to the track 16 rails, which relay is adjusted to' be normally de-encrgized, but to become-energized on occupancy of the block, to therebyvpick up and energize an approach signal through I its front point. r

In the case of long blocks, where it is necessary or desirable to connect the track circuit energy across the track rails at an intermediate portion of the block; as in a cut section, the above arrangement places the approach lighting relay too far away from the location of the approach signal to make it practical. In this case, an approach lighting relay connected as a line relay, is employed, but this has disadvantages since the approach lighting relay drops when the track relay drops, to thereby energize an approach signal through a back point, the back point giving poorer contact pressure than the front point, and tending to vibrate to cause flashing of the approach signal. Also the approach relay is usually in series with the wayside signal at the entrance of the preceding block, and hence must be of relatively high resistance, to-insure its release when the wayside signal is de-energized.

With the above and other considerations in view, it is proposed, in accordance with this invention, to provide a circuit for approach lighting, in connection with a cut section, wherein a relatively low resistance relay is normally connected .in's'eries with the preceding wayside signal, and is so adjusted that the approach relay,.- when so connected, is not energized to picked up position. Means are provided for shunting out the wayside signal at both ends of the tracksection, and connecting the approach relay through a shunt path across a source of energy, instead of in series with the wayside signal, whereby to pick up the low resistance approach relay and energize an approach signal through a front point of the' approach relay.

Further objects, purposes and characteristic features of the present invention will appear as thedescription progresses, reference being made to the accompanying drawing showing, solely by way of example, and in no manner whatsoever in a limiting sense, one form which the invention can assume.

In the drawing The figure of drawing shows a simplified circuit including one application of the present invention.

Referring to the drawing, there is represented a stretch of signal track constituted by track rails 1, having usual insulating joints 2, to define a relatively long track block with a battery B connected across the rails at an intermediate point. Across each end of the block is connected a track relay The various parts assume the positions and conditions as shown in the drawing, when the track section is unoccupied. Under these conditions, the wayside signal WS is energized through a circuit including a current limiting resistance r, the winding of relay AR, contact finger 6 and front point of relay TR contact finger 4 and front point of relay TR, signal WS, contact finger 3 and front point of relay TR, and contact finger 5 and front point of relay TR Upon a train entering the signal. block,

the track. relays TR and TR release,.to thereby shunt the wayside signal LVVS out of the approach relay circuit, and connect the approach relay across the source of en ergy through one or the other of two shunt.

One of these shunt paths includes paths. contact finger 6 and back point of relay TR a limiting resistance r, and wire 8; and the other shunt path includes contact finger 6 and front point of relay-TR w ire 9, contact finger 4- and back point of relay TR, current limiting resistance'r wireslO and 11, and contact finger 5 and front point of relay TR It is thus seen that on release of the track relays TR and T3 the approach relay AB, is connected in a shunt circuit to cause its energization, and upon picking up of its contact finger 7,.the approach sign'ahAS is energized througha circuit-which isobvious from the drawing, and inciuaes'con tact finger 7 and front. point of relay AR.

' If for any reason both of the track relays do not release, the approach relay AR. is nevertheless energized through one orfthe other of its shunt paths, as is obviousjfrom the above explanation.

On release of the track relays,fthe wayside signal WS, is short-circuited through a circuit including signal WS and contact finger 3 and back point of'relay TR. Here again if relay TR for any reason should fail to release but relay TR releases, then the short-circuit for the signal YVS includes contact finger 3 and front point of TR, wire 11, contact finger 5 and backpoint of TR wire 9, and contact finger 4% and front point of relay TR. v

From the above description it appears clear that on occupancy of the track section, the wayside signal is connected 'in 'a shortcircuit at one or theother end of the block, to thus protect it against energization by stray currents, and the approachfrelayis connected in a shunt circuit atone .or. the other end of theblock, in amannerto cause it to pick up and energize the',approach signal AS through a front point ofthe relay. e I i Vith an approach relay such as is generally employed, there is a much greater tendency for the contact fingers to vibrate, when dropping to a back point; than when operated by power to a front point, and-hence it is a considerable advantage to' 'arrangethe circuits so as to energize the 'approach' signal through a front point of the approach relay instead of through a back point.

It is also the case that the cont-act pressures are greater and more dependable at the front points, than at the back points, so that the:present-arrangement is of further advantage due to this fact.

.Thepresent arrangement of parts also permits using a relatively low resistance approachfrelay, With a low resistance approach relay, insufiicient current passes throughit when it is connected in series with a relatively high resistance wayside signal, such as. WVS,:to cause the approach relay to pick up, as explained above, and thus the arrangement of parts makes for "economy, since a low resistance relay is cheaper to manufacture than are high resistance relays. l T

Thefabove rather specific description of one form of the present invention, is given solely byway of'illustration, and is not intendechin any manner whatsoever, in a limiting sense. Obviously, the invention can assume many different physical forms, and is susceptible of numerous modifications, and all such forms and modifications, as are included within the scope of the appended claims, are intended to be covered by this application.

Having described my invention, I now claim':i

exile-In a :signal system, in combination, a

center feed track section, a wayside signal at the entrance end of the section, a normally de-energized approach signalat'the exit end of the section, an approach relay, and an energizing circuit for the approach signal including-a front point of the approach relay;

' 2. In: a signal system, in combination, a center feed track section, a wayside signal at the entrance endof the section, an approach signal at the exit end of the section, an approach relay, an energlzlng circuit for "the approach signal including a front point :of the approach relay, and means connecting "the approach relay in series, with the wayside signal when the block is unoccupied.

'- 3: In a signal system, in combination, a center feed track section, a wayside signal atthe entrance end'of the section, an approach signal at the exit end of the section,

an approach relay, an energizing circuit for the approach. signal including a front point of the approach relay, and .means connecting" the 1 approach relay in series with the wayside signal when the block is unoccupied,

said approach relay being of low resistance relative to theresistance of the wayside signal whereby to" become de-energized when connectedin series with the wayside signal.

irIn asignal system, in combination, a

center feedtrack section, a wayside signal at theentr'anceJend ofthe section, an approach signal at the exit end of the section, an approach relay, an energizing circuit for the approach signal including a front point of the approach relay, means connecting the approach relay in series with the wayside signal when the block is unoccupied, and means controlled by the track circuit for shunting the approach relay around the wayside signal to cause energization of the approach relay.

5. In a signal system, in combination, a center feed track section, a wayside signal at the entrance end of the section, an approach signal at the exit end of the section, an approach relay, an energizing circuit for the approach signal including a front point of the approach relay, means connecting the approach relay in series with the wayside signal when the block is unoccupied, and means controlled by the track circuit for shunting the approach relay around the wayside signal to cause energization of the approach relay and also short-circuiting the wayside signal to thereby protect it against energization by stray currents.

6. In a signal system, in combination, a center feed track section, a wayside signal at the entrance end of the section, an approach signal at the exit end of the section, an approach relay, an energizing circuit for the approach signal including a front point of the approach relay, means connecting the approach relay in series with the wayside signal when the block is unoccupied, a track relay at each end of the track section and means controlled by the track circuit for shunting the approach relay around the wayside signal, at each end of the track section, whereby to effect said shunting if only one of the track relays be operative.

7. In a signal system, in combination, a center feed track section, a wayside signal at the entrance end of the section, an approach signal at the exit end of the section, an approach relay, an energizing circuit for the approach signal including a front point of the approach relay, means connecting the approach relay in series with the wayside signal when the block is unoccupied, a track relay at each end of the track section and means controlled by the track circuit, for shunting the approach relay around the wayside signal, and for short-circuiting the wayside signal at each end of the track section, whereby to effect said shunting and said short-circuiting, if only one of the track relays be operative.

8. In a signal system, in combination, a center feed track section, a wayside signal, an approach signal, an approach relay, an energizing circuit for the approach signal including a front point of the approach relay, a track relay at each end of the track section, a circuit including front points of said track relays, in series, connecting the approach relay in series with the wayside signal when the section is unoccupied, and a plurality of shunt paths around the wayside signal, one including a back point of one track relay, and another a back point of each track relay, in series.

In testimony whereof I afiix my signature.

JOSEPH E. WILLING. 

